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.\" Author: Archie Cobbs <archie@FreeBSD.org>
.\" $Whistle: ng_UI.8,v 1.4 1999/01/25 02:37:56 archie Exp $
.\"
.Dd January 19, 1999
.Dt NG_UI 4
.Os
.Sh NAME
.Nm ng_UI
.Nd UI netgraph node type
.Sh SYNOPSIS
.In netgraph/ng_UI.h
.Sh DESCRIPTION
The
.Nm UI
node type has two hooks,
.Dv upstream
and
.Dv downstream .
Packets received on
.Dv downstream
must have 0x03 (indicating unnumbered information) as their first byte;
if not the packet is dropped.
This byte is then stripped and the
remainder of the packet sent out on
.Dv upstream .
.Pp
Conversely, packets received on
.Dv upstream
will have a 0x03 byte prepended to them before being forwarded out on the
.Dv downstream
hook.
.Sh HOOKS
This node type supports the following hooks:
.Bl -tag -width ".Va downstream"
.It Va downstream
Downstream connection.
Packets on this side of the node have a 0x03 as
their first byte.
.It Va upstream
Upstream connection.
Packets on this side of the node have the
initial 0x03 byte stripped off.
.El
.Sh CONTROL MESSAGES
This node type supports only the generic control messages.
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message, or when both hooks have been disconnected.
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr ngctl 8
.Sh HISTORY
The
.Nm
node type was implemented in
.Fx 4.0 .
.Sh AUTHORS
.An Julian Elischer Aq Mt julian@FreeBSD.org
